Prompt response to a cross-border plague outbreak in Zombo District, minimized spread, Uganda, March 2019

Abstract

Introduction: Plague, which is caused by the bacterium Yersinia pestis, is a priority zoonotic disease targeted for elimination in Uganda. On 6 March 2019, the Uganda Ministry of Health was notified of a patient in Zombo District with clinical presentation similar to pneumonic plague, and a positive plague rapid diagnostic test (RDT). We determined the scope of the outbreak, determined the mode of transmission, and recommended evidence-based control and prevention measures. Methods: A suspected pneumonic plague case was one with two or more of the following signs and symptoms: cough (bloody or wet), chest pain, difficulty in breathing, or fever in a resident of Zombo District during February 1-March 31, 2019. A confirmed case was a suspected case testing positive for Yersinia pestis by rapid diagnostic test, culture or serology. We actively searched for case-patients, traced contacts and took samples as appropriate. We performed descriptive epidemiology of the outbreak. Results: We identified one suspected and one confirmed pneumonic plague case. On February 26, 2019, a 4-year-old boy was buried in DRC near the Uganda border after succumbing to bubonic plague. Case-patient A (35-year-old mother to the boy), fell ill with suspected pneumonic plague while attending to him. She was referred to a health facility in Uganda on February 28 but died on arrival. On March 4, Case-patient B (23-year-old sister to Case-patient A), presented with pneumonic plague symptoms to the same Uganda facility and tested plague-positive by RDT, culture, and serological tests. Contacts (n=114) were traced and given prophylaxis; no new cases were reported. Conclusion: This fatal plague outbreak started as bubonic and later manifested as pneumonic. There was cross-border spread from DRC to Uganda with no cross-border efforts at prevention and control. Person-to-person transmission appears to have occurred. The quick and effective response likely minimized spread.